1. Field of the Invention
The invention relates to a self-propelled apparatus, and more particularly to the self-propelled apparatus that is equipped with an anti-drop system.
2. Description of the Prior Art
In domestic services, the self-propelled apparatus for indoor cleaning, also called as a cleaning robot, is itself a cleaning tool that needs no human involvement for a cleaning task, can perform the cleaning task automatically, and can suck in dusts and dirt while in waddling around the floor.
While the self-propelled apparatus moves on the floor, the route is usually preset in the apparatus, or the route is determined by applying an image-recognition means to judge the moving direction, the speed and the distance. However, since various indoor decorations and furniture may exist to different places from time to time, a preset fix scheme for the cleaning robot to follow is far from reality. In the case that the self-propelled apparatus may drop to be dysfunctional at a lower surface or more seriously may drop from a height, then the self-propelled apparatus might be damaged to an unworkable state.
In the art, a system with a set of sensors is implemented to protect the self-propelled apparatus from obstacles and/or dropping. Such a system is usually simply structured and less costly, but, in order to serve the detection purpose, the sensors are inevitably mounted to a front side of the main body of the self-propelled apparatus. Thus, some dropping risk may not be instinctively waived, and so unexpected dropping for the self-propelled apparatus is still possible.
In the art, to prevent the self-propelled apparatus from dropping from a height, an optical emitter and an optical receiver are introduced to be mounted obliquely inside the main body of the apparatus for detecting the distance between the infrared ray and the floor. In the case that a sum of the travelling distance of the emitting path and that of the receiving path changes, then it can be realized that the distance between the infrared ray and the floor is changed as well. Under such a circumstance, the self-propelled apparatus would be informed to turn, such that possible drop-from-height to the self-propelled apparatus can be avoided. When the receiving region and the emitting region do not have any overlapping, it implies that the distance between the self-propelled apparatus and the detection surface is too far, and thus a situation of meeting an obstacle is determined. To respond this situation, the self-propelled apparatus is turned or back off so as to avoid a possible damage from dropping-from-height. However, the design of obliquely mounting the optical elements includes complicated structuring and difficulty in disassembling and replacement. Hence, in the art, a lens module is introduced to deflect the lights emitted by the optical emitter.
As described above, it is obvious that all these prior arts would encounter a technical necking in detection distance and/or range. When the detection exceeds a predetermined range, then a problem in detection sensitivity would be inevitable. Further, if the power of the infrared emitter is lowered, then an inaccurate distance judgment would rise, even though the detection distance to the floor might be successfully shortened.